This paper attempts two things. Firstly, the limitations of the word "hedging" are discussed, and an alternative, hierarchically ordered, description of hedges and related phenomena is detailed, based on a distinction between proposition and comment (these terms refer, respectively, to what is said and what is said about what is said). Secondly, this alternative description is applied to academic medical writing, and in particular to its development over time, drawing on data from 1853 to the present. The hierarchy accounts well for the data, and shows the commentative language of academic medicine becoming increasingly formalised, with an increasing ratio of comment token to type as versions of "truth" presented in academic papers themselves become more formal, and split into two well-defined kinds, evidential truth (claims allowed by the conventions of statistics) and speculative truth (claims acknowledged as possibilities rather than certainties by the author/authors).